1. Field of the Invention
The present invention relates to a temperature sensor. In particular, it relates to an exhaust temperature sensor for detecting a temperature of an exhaust gas in an internal combustion engine.
2. Description of the Related Art
A general structure of an exhaust temperature sensor includes a sheath pin core wire electrically connected to a sensor portion for sensing a temperature, and a lead wire electrically connected to the sheath pin core wire for transmitting an output of the sensor portion to a control apparatus.
In general, a diameter of the sheath pin core wire is xcfx860.2 to 0.5 mm and the diameter of the lead wire is xcfx861.0 to 2.0 mm. When a tension acts on the sheath pin core wire and the lead wire, the sheath pin having a small diameter may be easily cut off.
Accordingly, usually, in order to prevent a tension on the lead wire acting on the sheath pin core wire, the lead wire is held by a bush made of rubber, and the bush and the lead wire are held and fixed by calking the bush so as to reduce the inner diameter of the protection tube in the state which the bush is mounted in the protection tube.
Recently, however, the vibration of an exhaust pipe has become large along with increase of an output of an engine so that the tension acting on the lead wire has also become large. Accordingly, it is very difficult to sufficiently reduce the tension acting on the sheath pin core wire in the conventional art.
Further, by giving slack to the lead wire in the protection tube, the tension acting on the lead wire is prevented from acting on the sheath pin core wire. However, since a compact size is required for the exhaust temperature sensor, it is very difficult to provide slack on the lead wire. As a result, it is very difficult to sufficiently reduce the tension acting on the sheath pin core wire.
The present invention aims to sufficiently reduce the tension acting on a sheath pin core wire.
Further, the present invention aims to provide a temperature sensor having a sufficiently low tension acting on the sheath pin core wire.
In accordance with an aspect of the present invention, there is provided a temperature sensor including: a sensor body for sensing a temperature; a sheath pin core wire electrically connected to the sensor body; a connector electrically connecting between the sheath pin core wire and the lead wire; and a protection tube for containing the connector and the sheath pin core wire, and for protecting the connector and the sheath pin core wire; wherein a connection portion between the sheath pin core wire and the lead wire, including the connector, is hardened by a ceramic material so that a molded portion is provided; and wherein a displacement limiting means is provided for limiting the displacement of the molded portion, exceeding a predetermined value in the protection tube.
In accordance with another aspect of the present invention, there is provided a temperature sensor including: a sensor body for sensing a temperature; a sheath pin core wire electrically connected to the sensor body; a connector electrically connecting between the sheath pin core wire and the lead wire; a protection tube for containing the connector and the sheath pin core wire, and for protecting the connector and the sheath pin core wire; and a bush for holding and fastening the lead wire for the protection tube by holding the lead wire; wherein a connection portion between the sheath pin core wire and the lead wire, including the connector, is covered by a tube, and the tube is fixed to the lead wire.
In accordance with still another aspect of the present invention, there is provided a temperature sensor including: a sensor body for sensing a temperature; a sheath pin core wire electrically connected to the sensor body; a connector electrically connecting between the sheath pin core wire and the lead wire; a protection tube for containing the connector and the sheath pin core wire, and for protecting the connector and the sheath pin core wire; and a bush for holding and fastening the lead wire for the protection tube by holding the lead wire; wherein the bush is made of metal and the lead wire is held by the bush by calking the bush so as to reduce a cross-sectional area of the bush.
In accordance with still another aspect of the present invention, there is provided a temperature sensor including: a sensor body for sensing a temperature; a sheath pin core wire electrically connected to the sensor body; a metal connector electrically connecting between the sheath pin core wire and the lead wire; a protection tube for containing the connector and the sheath pin core wire, and for protecting the connector and the sheath pin core wire; and a bush for holding and fastening the lead wire for the protection tube by holding the lead wire; wherein a stopper is provided for limiting displacement of the connector due to collision of the connector exceeding a predetermined value within the protection tube.
In accordance with still another aspect of the present invention; there is provided a temperature sensor including: a sensor body for sensing a temperature; a sheath pin core wire electrically connected to the sensor body; a cylindrical sheath pin for covering the sheath pin core wire; a connector electrically connecting between the sheath pin core wire and the lead wire; and a protection tube for containing the connector and the sheath pin core wire, and for protecting the connector and the sheath pin core wire; wherein a bridge member is provided, one end of the bridge member is fixed to the lead wire, and the other end of the bridge member is fixed to the sheath pin.
In accordance with still another aspect of the present invention; there is provided a temperature sensor including: a sensor body for sensing a temperature; a sheath pin core wire electrically connected to the sensor body; a cylindrical sheath pin for covering the sheath pin core wire; a relay sheath pin core wire electrically connecting between the sheath pin core wire and the lead wire; and a cylindrical sheath pin for containing the relay sheath pin core wire in the fixed shape.
In accordance with still another aspect of the present invention; there is provided a temperature sensor including: a sensor body for sensing a temperature; a sheath pin core wire electrically connected to the sensor body; a metal connector for electrically connecting between the sheath pin core wire and the lead wire; and a protection tube for containing the connector and the sheath pin core wire, and for protecting the connector and the sheath pin core wire; wherein a stopper is provided for limiting displacement of the connector exceeding a predetermined value due to collision of the connector within the protection tube, the stopper includes a cylindrical portion for covering the connector; and the cylindrical portion covers portions of the connector except for a connecting portion of the sheath pin core wire.